This invention relates to an improved latching mechanism, for selectively and alternatively latching one of two relatively sliding members, disposed on opposite sides of an internal member, to that internal member. More particularly, this invention relates to such a latching mechanism as embodied in a convertible pliers.
In conventional pliers, or pliers-type tools, a pair of elongated members are pivotally connected to each other in an X arrangement, wherein the longer ends of said members at one side of said pivot define handles and wherein the shorter ends of said members on the other side of said pivot define working jaws or implements. In certain pliers-type tools, such as retaining ring pliers, it is desirable that the working jaws or implements are imparted with different movements in response to the squeezing or moving together of the handles. In one mode of operation it may be desirable that the jaws or elements move toward each other in response to movement of the handles toward each other; and in another mode of operation it may be desirable that the jaws or implements move away from each other in response to movement of the handles toward each other.
A pliers-type tool which enables both modes of operation is sometimes referred to as a convertible pliers; and one form of such convertible pliers requires a latching mechanism enabling the latching or coupling of the jaws or implements alternatively to the two handles. A retaining ring pliers of this type is described and claimed in the applicant's U.S. Pat. No. 4,280,265 issued July 28, 1981. In the retaining ring pliers described in that patent the handles are urged away from each other by a biasing spring. The jaws of the pliers carry retaining ring tips for engagement with the lug holes of either internal or external retaining rings. In one mode of operation the jaws are moved away from each other in response to movement of the handles toward each other to place and remove external retaining rings. In the other mode of operation the jaws are moved toward each other in response to movement of the handles toward each other to place and remove internal retaining rings.
In pliers-type tools of the type described it is frequently necessary or desirable that the movement of the tool jaws be precise and that, accordingly, the coupling between the jaws and the handles be as rigid as possible. It may be important then that a latching mechanism, of the type which is the subject of this invention, provide a rigid coupling between the handle and the particular tool jaw to which it is selectively coupled.
In pliers-type tools as described above a single pliers is frequently used with different sizes of work objects; and for this purpose it is frequently desirable to use different sizes of implement tips in association with the convertible pliers. With respect to a retaining ring pliers for example, retaining rings come in many sizes having lug holes of corresponding varying size; and it is desirable to be able to use multiple tips in association with such pliers to accommodate the pliers to rings of various size. In a retaining ring pliers, the tips are typically mounted at the distal ends of elongated pliers jaws; and in a pliers as described in the above mentioned U.S. patent for example, the elongated tips are received in recesses generally aligned with the elongated jaws.
For some uses of a retaining ring pliers, it is desirable that the operator posts of the retaining ring tips, which are received in the lug holes of the retaining ring, be angled relative to the shanks of the tips. In this situation, the load on the tips when the pliers is used exerts a force tending to rotate the tips within the respective jaws. To obviate such rotation it is desirable that the shanks of the tips have a coacting relation with the recesses in the distal ends of the jaws, so that the tips cannot rotate under load within the mounting recesses.
Where pliers-type tools as above described are used with relatively large or heavy retaining rings for example, the load resistance in use is considerable. For some applications, the retaining ring must be placed precisely and carefully within a confined area, and this may be difficult for a user to do when he must maintain manually the desired compression on the handles in order to manipulate the retaining ring. To facilitate such operation it is desirable that the pliers have spring means biasing the handles apart and cooperating ratchet means for locking the handles together in a desired relationship. Pliers with this desired feature should also have ready means for releasing the ratchet mechanism when desired.
An object of this invention is to provide an improved latching mechanism for selectively and alternatively joining relative movable external members to a common internal member.
Another object of this invention is to provide such improved latching mechanism which is particularly adapted for use with a convertible pliers or pliers-type tool.
A further object of this invention is to provide such improved latching mechanism which provides an improved and more durable and rigid linking or coupling between the tool handles and the tool jaws.
Still another object of this invention is to provide a pliers-type tool having means for mounting implement tips in the respective jaws in a manner that the tips will not rotate under load.
A still further object of this invention is to provide a convertible plier-type tool having means for locking the tool handles in a desired relationship.
Another object of this invention is to provide a latching mechanism as above described wherein latching members project from the face of one handle or external member, and may be very readily and easily shifted by the user to engage the jaw with the other respective handle or external member.
These objects are accomplished in a pliers which includes a pivot, first and second jaws arranged for oscillation toward and away from each other about that pivot, and first and second handles arranged for oscillation toward and away from each other about that same pivot. The handles have portions disposed on respective opposite sides of the jaws adjacent to the pivot. An elongated latch pin is disposed in each jaw for alternative and selective engagement with one or the other of the handles. The latch pins are disposed in transverse bores having axes parallel to the axis of the pivot, and each of the handles has a pair of spaced holes positioned to receive the latch pins. The latch pins in the first and second jaws are selectively engaged in the holes of respective first and second handles, to effect movement of the jaws toward each other when the handles are moved toward each other; and the latch pins in the first and second jaws are selectively engaged in the holes of the respective second and first handles to effect movement of the jaws away from each other when the handles are moved toward each other.
The improvement in the pliers is that the latch pins are elongated and generally cylindrical and are received in generally cylindrical bores within the jaws, these bores having however an elongated recess in one wall. Each pin has an external annular groove intermediate its ends to receive a C-shaped circular spring having a tangential tab. The springs are configured to be disposed within the annular grooves with the spring tab projecting into the elongated recesses. The holes of the handles have diameters substantially the same as those of the bores and latch pins to provide rigid coupling between the handles and jaws.
More particularly the pliers jaws are elongated and have linear multi-sides recesses for receiving the linear shanks of implement tips, which shanks have a coacting multi-sided cross section.
Also more particularly the pliers handles are provided with spring means for expanding the handles and ratchet means for maintaining the handles in a selected contracted condition.
The novel features and the advantages of the invention, as well as additional objects thereof, will be understood more fully from the following description when read in connection with the accompanying drawings.